Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752972AbdFSXkQ (ORCPT ); Mon, 19 Jun 2017 19:40:16 -0400 Received: from mail-pf0-f171.google.com ([209.85.192.171]:34992 "EHLO mail-pf0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752647AbdFSXgt (ORCPT ); Mon, 19 Jun 2017 19:36:49 -0400 From: Kees Cook To: kernel-hardening@lists.openwall.com Cc: Kees Cook , David Windsor , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH 05/23] befs: define usercopy region in befs_inode_cache slab cache Date: Mon, 19 Jun 2017 16:36:19 -0700 Message-Id: <1497915397-93805-6-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1497915397-93805-1-git-send-email-keescook@chromium.org> References: <1497915397-93805-1-git-send-email-keescook@chromium.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1918 Lines: 53 From: David Windsor The befs symlink pathnames, stored in struct befs_inode_info.i_data.symlink and therefore contained in the befs_inode_cache slab cache, need to be copied to/from userspace. In support of usercopy hardening, this patch defines a region in the befs_inode_cache slab cache in which userspace copy operations are allowed. This region is known as the slab cache's usercopy region. Slab caches can now check that each copy operation involving cache-managed memory falls entirely within the slab's usercopy region. This patch is modified from Brad Spengler/PaX Team's PAX_USERCOPY whitelisting code in the last public patch of grsecurity/PaX based on my understanding of the code. Changes or omissions from the original code are mine and don't reflect the original grsecurity/PaX code. Signed-off-by: David Windsor [kees: adjust commit log] Signed-off-by: Kees Cook --- fs/befs/linuxvfs.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/fs/befs/linuxvfs.c b/fs/befs/linuxvfs.c index 63e7c4760bfb..893607591805 100644 --- a/fs/befs/linuxvfs.c +++ b/fs/befs/linuxvfs.c @@ -442,11 +442,15 @@ static struct inode *befs_iget(struct super_block *sb, unsigned long ino) static int __init befs_init_inodecache(void) { - befs_inode_cachep = kmem_cache_create("befs_inode_cache", - sizeof (struct befs_inode_info), - 0, (SLAB_RECLAIM_ACCOUNT| - SLAB_MEM_SPREAD|SLAB_ACCOUNT), - init_once); + befs_inode_cachep = kmem_cache_create_usercopy("befs_inode_cache", + sizeof(struct befs_inode_info), 0, + (SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD| + SLAB_ACCOUNT), + offsetof(struct befs_inode_info, + i_data.symlink), + sizeof_field(struct befs_inode_info, + i_data.symlink), + init_once); if (befs_inode_cachep == NULL) return -ENOMEM; -- 2.7.4